PLOS Global Public Health (Jan 2022)

Seroprevalence of SARS-CoV-2 in four states of Nigeria in October 2020: A population-based household survey.

  • Rosemary A Audu,
  • Kristen A Stafford,
  • Laura Steinhardt,
  • Zaidat A Musa,
  • Nnaemeka Iriemenam,
  • Elsie Ilori,
  • Natalia Blanco,
  • Andrew Mitchell,
  • Yohhei Hamada,
  • Mirna Moloney,
  • Emem Iwara,
  • Alash'le Abimiku,
  • Fehintola A Ige,
  • Nwachukwu E William,
  • Ehimario Igumbor,
  • Chinwe Ochu,
  • Adesuyi A Omoare,
  • Olumide Okunoye,
  • Stacie M Greby,
  • Molebogeng X Rangaka,
  • Andrew Copas,
  • Ibrahim Dalhatu,
  • Ibrahim Abubakar,
  • Stephen McCracken,
  • Matthias Alagi,
  • Nwando Mba,
  • Ahumibe Anthony,
  • McPaul Okoye,
  • Catherine Okoi,
  • Oliver C Ezechi,
  • Babatunde L Salako,
  • Chikwe Ihekweazu,
  • Nigeria SARS-CoV-2 Survey Group

DOI
https://doi.org/10.1371/journal.pgph.0000363
Journal volume & issue
Vol. 2, no. 6
p. e0000363

Abstract

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The observed epidemiology of SARS-CoV-2 in sub-Saharan Africa has varied greatly from that in Europe and the United States, with much lower reported incidence. Population-based studies are needed to estimate true cumulative incidence of SARS-CoV-2 to inform public health interventions. This study estimated SARS-CoV-2 seroprevalence in four selected states in Nigeria in October 2020. We implemented a two-stage cluster sample household survey in four Nigerian states (Enugu, Gombe, Lagos, and Nasarawa) to estimate age-stratified prevalence of SARS-CoV-2 antibodies. All individuals in sampled households were eligible for interview, blood draw, and nasal/oropharyngeal swab collection. We additionally tested participants for current/recent malaria infection. Seroprevalence estimates were calculated accounting for the complex survey design. Across all four states, 10,629 (96·5%) of 11,015 interviewed individuals provided blood samples. The seroprevalence of SARS-CoV-2 antibodies was 25·2% (95% CI 21·8-28·6) in Enugu State, 9·3% (95% CI 7·0-11·5) in Gombe State, 23·3% (95% CI 20·5-26·4) in Lagos State, and 18·0% (95% CI 14·4-21·6) in Nasarawa State. Prevalence of current/recent malaria infection ranged from 2·8% in Lagos to 45·8% in Gombe and was not significantly related to SARS-CoV-2 seroprevalence. The prevalence of active SARS-CoV-2 infection in the four states during the survey period was 0·2% (95% CI 0·1-0·4). Approximately eight months after the first reported COVID-19 case in Nigeria, seroprevalence indicated infection levels 194 times higher than the 24,198 officially reported COVID-19 cases across the four states; however, most of the population remained susceptible to COVID-19 in October 2020.